Urban Heat and Health

Physicians and physiologists understand the human body’s responses to extreme heat better than architects or other professionals do. As heat waves increase in intensity and frequency, however, gaining an understanding of these responses and the conditions that cause them is becoming more critical for the AEC community. Awareness of these bodily processes empowers us to better help our communities thrive despite rising temperatures; it underlies and justifies the adaptive mitigation measures taken on collective levels. Emergency physician Elan Levy gave the largely nonmedical audience a practical overview on the topic: when air temperatures exceed core body temperature and/or humidity prevents sweat from evaporating, particularly in someone who is unacclimatized to hot conditions or influenced by age, medications, or disease, a cascade of dysfunctions impairs the cardiovascular, respiratory, and central nervous systems. The result is heat stroke, either exertional or non-exertional; the latter is “classical” heat stroke, and involves dehydration.

Heat waves as severe as the 2003 Parisian event, which Richard Keller profiled in depth, result in mortality that is disproportionate to expectations. We should be able to improve our predictions, however; vulnerability to hyperthermia is not random. That said, it is also not simple: along with the intuitive associations with old age, infirmity, and poverty, heat vulnerability also varies with aspects of building and district design, social support networks, and demographics. For example, high-rise buildings with fragmented social cohesion patterns correlate with high health risks. “One of the key challenges of heat waves is that they really do target the people who are most difficult to reach,” noted moderator Eric Klinenberg, who called for neighborhood designs that are more conducive to the social networks that safeguard vulnerable populations, sometimes even more so than physical infrastructure. Klinenberg, who studied the 1995 Chicago heat wave in depth, extrapolated from Chicago’s three-day event and the longer 2003 European heat wave that a comparable event in any American city would strain its hospitals and other systems to the breaking point. In 1995, half of Chicago’s hospitals went on bypass status, rejecting and redirecting further emergency patients. Power-grid failures, such as those experienced during Sandy, would incapacitate our current elevators and water pumps, turning high-rise residences into deathtraps.

Vulnerability to hyperthermia is neither random nor simple: along with the intuitive associations with old age, infirmity, and poverty, heat vulnerability also varies with aspects of building and district design, social support networks, and demographics.

Fortunately, analysis of past mortality patterns and infrastructural failures can inform future decisions about communities’ design and character. Sociologist and filmmaker Sabrina McCormick, having observed the state of heat-related research and preparation in several U.S. cities, noted that most adaptation programs are in the early stages of development. Though New York City is “ahead of the curve” in some ways, our public cooling center approaches face perceptual obstacles, she has found, and the need for better heat education matches that of other cities. New York City officials Tom Matte and Melissa Umberger, of the respective Departments of Health and Emergency Management, elaborated on some of the city’s efforts to combat heat-related illnesses, as well as thermal exacerbation of chronic disorders, specifically citing easier access to cooling for high-risk populations and multi-faceted informational campaigns as top priorities.

Post-Sandy New York, Matte underscored, is indeed planning for future scenarios with post-emergency canvassing operations, among other carefully thought out measures. When considering the tendency for heat waves to worsen multisystem stresses – Keller cited the combination of heat, prolonged drought, forest fires, and power outages in 2003, resulting in €4 billion in agricultural losses in Europe – those measures become even more urgent priorities. “We’re about to invest a lot of collective resources over the next decades in climate security,” Klinenberg summarized. He then warned: “If we do climate security the way we did homeland security, we’re in big trouble.”